Arabinose 5-phosphate analogues as mechanistic probes for Neisseria meningitidis 3-deoxy-D-manno-octulosonate 8-phosphate synthase.
3-Deoxy-D-manno-octulosonate 8-phosphate (KDO8P) synthase catalyses the condensation reaction between phosphoenolpyruvate and D-arabinose 5-phosphate (D-A5P) in a key step in lipopolysaccharide biosynthesis in Gram-negative bacteria. The KDO8P synthase from Neisseria meningitidis was cloned into Escherichia coli, overexpressed and purified. A variety of D-A5P stereoisomers were tested as substrates, of these only D-A5P and l-X5P were substrates. The Asn59Ala mutant of N. meningitidis KDO8P synthase was constructed and this mutant retained less than 1% of the wild-type activity. These results are consistent with a catalytic mechanism for this enzyme in which the C2 and C3 hydroxyl groups of D-A5P and Asn59 are critical.
Ahn
Meekyung
M
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
Cochrane
Fiona C
FC
Patchett
Mark L
ML
Parker
Emily J
EJ
D000446:Aldehyde-Lyases / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D009345:Neisseria meningitidis / Q000201:enzymology*; D010428:Pentosephosphates / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D010728:Phosphoenolpyruvate / Q000737:chemistry / Q000378:metabolism; D013237:Stereoisomerism
D010428:Pentosephosphates; C028055:arabinose 5-phosphate; D010728:Phosphoenolpyruvate; C020011:2-dehydro-3-deoxyphosphooctonate aldolase; D000446:Aldehyde-Lyases